Rotating combustion chamber for rocket apparatus



Feb. 19, 1946. R. H. GODDARD ROTATING COMBUSTION CHAMBER FOR ROCKETAPPARATUS Filedct. 12, 1942 2 sheets-sheet 1 Feb. 19, 1946. R, H.GODDARD ROTATING COMBUSTION CHAMBER FOR ROCKET APPARATUS Filed 001;. l2,1942 2 Sheets-Sheet 2 Palmares. 19,1946 'j UNITED. STATES PATENT OFFICEy" l '.ifasaurpw M Robert H. Goddard, Roswell, N. Mex., assignor ofone-half to The Daniel and Florence Grupv genlieim Foundation, New York,N. Y., a oorporation of New `York Application october 12, 1942. serialNo. 461,671

y (Creo-35.6)

20 Claims.

This invention relates to rocket apparatus adapted for use in aircraft,and relates more particularly to rocket apparatus in which thecombustion chamber is rotated during the 'combustion operation. f

It is one important object of my invention to provide means for directlyincreasing the feed pressure of the coacting combustion liquids by therotation of the combustion chamber itself and by a very simple andreliable lconstruction thereof.

I also provide means for producing initial rotation of the combustionchamber; means for controlling the speedcf rotation of the chamber;automatic means to counteract the gyrascopic effect of the rotatingchamber; means to prevent the escape of combustion liquids from theapparatus; improved means for jacketing and cooling the walls of thecombustion chamber and its associated discharge nozzle; and improvedmeans for effecting high-speed injection of a combustion mixture intothe body of the.

combustion chamber.

Another feature of the invention is the attainment of very thoroughmixing and high-speed injection of the combustion liquids by preliminarycombustion of a small or fractional amount of said liquids.

My invention further relates to arrangements and combinations of partswhich will be hereinafter described and more particularly pointed out inthe appended claims.

Preferred forms of the invention are shown in the drawings, in whichFig. 1 is a sectional front elevation of my improved combustion chamberand associated Darts;

Fig. 2 is an enlarged detail sectional view of a part shown in Fig. land to be described;

Fig. 3 is an enlarged detail sectional view, taken along the line 3-3 inFig. 1;

Fig. 3a is an enlarged detail sectional view of certain dischargeopenings, to be described;

Fig. 4 is a perspective view of a feeding device or nozzle to bedescribed; l 1 l Figs. 5, 6 and 'I are partial sectional frontelevations of certain modiiled chamber constructions; y

Fig. 8 is a partial sectional plan view, taken along the line 8-8 inFig. 5;

Fig. 9 is a front elevation of pressure-supplying apparatus to be usedwith the construction shown in Figs. and 8;

fled construction for counteracting gyroscopic force;

Fig. 11 is an enlarged partial detail plan view, looking' inthedirection of the arrow il in Fig. 10: K'

Fig. 12 is a partial sectional front elevation of the upper portion of acombustion chamber provided with sealing devices; v

Fig. 13 is a partial plan 1view of a sealing ring used therein and to bedescribed; l

Fig. 14 is a sectional front elevation of the lower portion of acombustion chamber, also provided with sealing jdevices; and

Fig. 15 is a detail sectional plan view of a portion of the nozzle outercasingshown in Fig. 10.

Referring to Figs. 1r to 4, my improved combustion chamber C comprisesan outer casing 20, an upper inner casing member or chamber wall 2l, anda lower inner casing member or chamber wall 22. I also provide adischarge nozzle 23 and an outer casing 24 for the nozzle 23. All of theparts thus far described are permanently secured together to form asingle rotating unit which is preferably supported on radialantifriction bearings 21 and 28 in which the unit is firmly supportedbut freely rotatable.

Ribs or partitions 30 are interposed between the outer casing 20 and theinner casing members ,2l and 22, and these partitions serve to hold theparts in desired spaced relation and also to direct the combustionliquids toward the ignition area and to give said liquids a rapid rotarymotion, thus generating a substantial centrifugal force therein. Similarpartitions Sill'L are used in the nozzle.

It will be noted that the inner casing members 2| and 22 graduallyapproach the outer casing 20 as the casing and casing members increasein diameter, thereby maintaining the spacing area between the innermembers and the outer casing more nearly uniform.

Certain of the partition members in the chami I end ofthe combustionchamber and "preferably series of balls 36 to form a thrust bearing toresist the upward force generated by the discharge of Fig. 10 is asectional front elevation of a modi- 55 combustion gases from the nozzle23.

space S between the outer casing and thegupper casing member-2l from thespace S' between the outer casing 20 and the lower casing member.

The lower end ofthe upper casing member 2l is inwardly curved or offsetas shown in Fig. 1 and is connected to the annular mixing ring 40 by anend plate or partition 45. The upper end of the lower casing member 22is similarly inwardly curved or offset and is connected to the annularmixing ring 40 by an end plate or partition 45.

Nozzle or-port openings 41 and 48 are provided at the edges of the ring40, and these openings are preferably formed as shown in Fig. 2 with anenlarged or countersunk outer portion 49, so that the effective lengthof each nozzle opening 41 or 43 is relatively short. The upper and loweropenings 41 and 48 are preferably so disposed that jets of thecombustion liquids enter at an intersecting angle, as shown in Fig. l,with the resultant mixture thereafter directed radially outward into theannular mixing ring before being ejected inward to the combustionchamber C through the annular space S2 between the diverging flanges 45and 46. It will be noted that these iianges are both inclined upwardly,so that the escaping combustible mixture is directed diagonally upwardtoward the ignition device 32. The

' greater mass and momentum of the oxygen assists in directing the fuelmixture upwardly. T he gases thus remain longer in the combustionchamber C, insuring good combustion. The ring 40 has a relatively thickwall and coacts with the annular space S2 as follows: The liquidsentering through the nozzle openings 41 and 48 impinge on each other.scatter, and then strike the inside surface of the ring 40. There issome preliminary combustion in the space enclosed by the ring 40, andthis preliminary combustion generates enough pressure to force thepartially burned mixture rapidly through the inwardly expanding spaceS2, so that it enters the body of the chamber C at high speed. Thisproduces very thorough mixing of the combustion liquids and over- 'comesthe outward centrifugal force. This space 2,395,114 'rheigmun device a2is not shown 1n detau surface of the ring 40 byjthe spray resulting fromthe impinging streams.

One of the combustion liquids, as gasoline, is

preferably admitted tangentially to the upper jacket space S from anozzle 55 through an annular opening 56 in the upper end flange 51 ofthe outer casing 20. The ow through the nozzle 55 may be controlled byaxial adjustment of a plunger 58 (Fig. 4).

The other combustion liquid, as liquid oxygen, may be suppliedtangentially to the lower space S by a similar nozzle 60 directedthrough an annular inlet slot or opening 5l at the lower end of theouter casing 20.

Athird nozzle 52 injects a cooling liquid tangentially through anannular inlet opening 53 to the jacket space S3l between the dischargenozzle 23 and its outer casing 24.

The lower end of the outer casing 20 is preferably provided with arecurved portionor inner flange 64 at its lower end to prevent down-flowand escape of the injected liquid. The upper end of the outer nozzlecasing 24 is bent inward to provide a flange 66 to prevent escape of thecooling liquid which may be liquid oxygen. or water or any othernon-combustible liquid. This liquid is supplied for cooling purposesonly and does not enter the combustion chamber. An annular partition 68separates the inlet openings 6i and 63.

The end wall 10 below the space S3 is perforated as indicated at 1I topermit escape of the cooling liquid injected through the opening 53 orvapor or steam formed therefrom. The liquids delivered through thenozzles 55, 50 and 62 may come from any suitable storage supply underpressure. The holes 1| are preferably helically disposed in order toassist in producing rotation of the chamber. These holes also preferablyincrease in cross section in the direction of out- 40 flow, as shown at1I (Fig. 3a), and produce a S2 is of increasing cross section in thedirection l of flow, and thus acts somewhat like an expansionnozzle inincreasing the velocity.

'Ihe wall of the ring 40 is made thick enough so that the inne'r surfacecan be ycomparatively warm and hence produce some vaporizing of themixed liquids, while the outer surface remains cool and does not produceboiling in the spaces Sand SI.

nozzle reaction.

To produce automatic rotation of the combustion chamber C, the innerwall of the nozzle 23 is provided with spirally disposed ribs 14 whichcoact with the discharge gases to exert a strong rotative force on thechamber. In order to prevent excessive speed of rotation of the chamber,I provide brake devices 16, pivoted at 11 on a ring 18 secured to theoutside of the nozzle casing 24. These brake devices 15 are movedoutward by centrifugal force and drag against a fixed brake band 19.

The detailedconstruction of these brake devices may be the same as isshown in Figs. 10 and 11, in connection with which figures a moredetailed description will be given.

A combustion chamber constructed as above described possesses many andimportant advantages. The combustion liquids enter at points ofrestricted diameter of the chamber and are both caused to flow outwardand toward the annular mixing ring 40 by centrifugal force. This forcealso supplies pressure for ejecting the liquids through the portopenings 41 and 48. The spaces S and S' constitute fluid-filled coolingjacket spaces about the combustion chamber and the space S3 serves thesame purpose for the discharge nozzle.

This makes it possible to construct the combustion chamber and nozzle ofrelatively thin sheet metal which, when thus jacketed, will withstandthe intense heat developed in the combustion chamber. The rotation ofthe chamber, being caused by the reaction of the discharge gases onVtank M5.

the ribs '14,I is entirely automatic and the speed ot rotation isvautomatically controlled by the brake devices 16.

With this very simple construction,'1 am thus able to attain veryefficient mixing of the combustion liquids and equally efcient coolingof the metal surfaces exposed to the combustion gases. The rapidrotation of the port openings or slots causes similar rapid rotation ofthe fuel mixture and combustion gases in the chamber. The cooler andheavier gases will remain near the chamber walls, while the hotter andmore completely consumed gases will move away from the walls.

In Figs. y, 6 and 7 I have shown modified constructions of thecombustion chamber walls at their points of greatest diameter. In Fig.5, the upper part 80 and the lower part 8| of the rotating combustionchamber are formed as separate hemispherical 'units having theiradjacent end portions secured together by a strong and relatively heavy)encircling band 82. 'I'he adjacent l ends of the parts 80 and 8| arespaced apart to provide a mixing recess 83, and preferably staggeredslots or openings 84 (Fig. 8) are formed in the adjacent ends, throughwhich slots the combustion liquids are delivered.

The construction shown in Fig. 6 is similar to that shown in Fig. 5,except that the openings 8l in the adjacent ends of the chamber portions88 and 89 are directed outward into an annular recess 90, so that moreactive agitation before ignition may take place. The parts 88 and 89 arejoined by an annular band 9|, as in the previous construction.

In Fig. 7, the upper chamber portion 94 and the lower portion 95 arejoined by a band 96 as previously described. The adjacent ends of thechamber portions 94 and 95 are abutted, however, and have inwardlybeveled end surfaces 9`| and 00 -provided with nozzle or port openings99. In this construction, the jets` of liquid are discharged alongintersecting paths directly into the combustion chamber. Fillets |00 maybe provided at each side of the separating partition |0| and also asshown at |00 in Figs. 5 and 6. Either staggered slots or circular portopenings may be used in any of the chamber constructions.

With all forms of my invention, it is desirable to provide means foreffecting initial rotation and for this purpose I provide an annularring ||0 having a plurality of bucket recesses l I (Fig. 8) coactingwith a nozzle.v I I2. The nozzle lf2 may be supplied with compressed airor other cornpressed gas through a pipe ||4 (Fig. 9) from a The deliveryof compressed air may be controlled by a valve IIB, convenientlyoperated by a cord and normally closed by a spring ll. By pulling thecord IH and holding the valve open for a short period, the combustionchamber may be given its necessary initial rotation.

The rotation of the combustion chamber C produces a considerablegyroscopic effect and a certain amount of angular momentum which may insome cases interfere with steering a rocket craft. This gyroscopiceffect may be more or less counteracted by the auxiliary constructionshown in Fig. 10, in which a ring |20 is mounted at the discharge end ofthe nozzle 22a, which nozzle is constructed as previously described,except that the discharge openings 1Ib (Fig. 15) are in the outer casing24a rather than in the end wall of the nozzle. The openings ||b aretosome extent tangential to assist in producing rotation, and arepreferably also in the form of expanding nozzles, such as are alsorshown in Fig. 3a. The ring |20 is freely rotatable in ball bearings |2|and supports an annular disc |22, which in turn supports a relativelyheavy annular band |23.

The inner surface of the ring |20 is provided with spiral ribs |25 whichare, however, reversely disposed with respect to the ribs 14 in theassociated nozzle. Consequently, as the combustion gases leave thedischarge nozzle after effecting rotation of the combustion chamber andnozzle in one direction, these gases encounter the ribs |25 in the band|20 and cause rapid rotation of the ring |20, associated disc |22 andband |23 in the reverse direction. Consequently a second gyroscopicforce is developed which more or less neutralizes the gyroscopic effectof the rotating combustion chamber,

The speed of rotation of the ring |20, flange |22 and associated partsmay be controlled by brake devices |21 (Fig. 11), norm-ally drawn inwardby springs |28 but moved outward by centrifugal force to engage a fixedbrake band |29 and thus prevent an excessive speed of rotation of theauxiliary parts.

It is desirable to prevent escape of any of the liquids supplied throughthe nozzles 55, 50 and 52, as mixtures of vapors of these liquidscollecting in any enclosed space outside of the cornbustion chambermight be explosive and very dangerous. I accordingly find it desirableto provide the sealing devices shown in Figs. 12 to 14 and which I willnow describe.

The devices shown in Figs. 12 and 13 are provided at the top of thecombustion chamber C to prevent the escape of liquid oxygen injectedfrom the nozzle 55 and designed to enter the combustion chamber throughthe annular opening 56. These devices comprises a stationary at annularcasing or jacket |30 enclosing the upper end of the combustion chamber.I extend the outer casing 20a of the combustion chamber into the jacket|30 and provide an inwardly directed vane or slinger ||3| and anoutwardly directed vane or slinger |32 adjacent the upper and lowerinner flat surfaces of the jacket |30. These varies have only slightclearance relative to the jacket surfaces.

I also provide the jacket |30 with a depending flange |33 runningclosely adjacent the upper end of the combustion chamber casing 208,

and I provide the jacket with a suitable drain thrown or otherwiseremoved through the drain pipe 34. The slinger |32 very effectuallyopposes pass/age of liquid through the narrow space between the casing20EL and the lower surface of the jacket, and the flange |33additionally prevents escape of liquid or any vapor thereof from thejacket.

It is also desirable to seal the space between the rotating ignitiondevice 32 andthe upper end of the jacket |30 when the apparatus is atrest, and for this purpose ,I provide a natural or synthetic rubber band|40 of circular cross section and having a considerable number of leadballs |4| embedded therein. When the apparatus is at rest, the band |40is seated between a flange |42 on an upward extension of the jacket |30and a flange |43 on the rotating igniter 32. v

When the combustion chamber and igniter are rotated, even at low speed,centrifugal force acting on the lead balls |4| expands the band |40 asshown in dotted lines in Fig. 12, so that it does not engage thestationary ange- |42. This relieves the starting motor. A cover |44mounted on the igniter 32 limits outward displacement of the band |40andvalso protects the associated parts from dirt or injury.

A somewhat similar sealing construction for the nozzles 60 and 62 isshown in Fig. 14, in

which a fixed annular jacket |50 surrounds the restricted connectionbetween the lower end of the combustion chamber C and the upper end ofthe discharge nozzle 23.

The lower end of the outer casing 2|JL of the combustion chamber isprovided with an outwardly projecting annular vane or slinger |5|, andthe upper end of the outer casing 24b of the nozzle is provided with anoutwardly projecting vane or slinger |52. The jacket |50 is providedwith a depending flange |54 embracing the upper end of the outer casing24b of the nozzle. A drain pipe |55 is provided for the jacket |50. Thevanes |5| and |52 and the flange |54 all run with slight clearance.

With this construction, liquid from the nozzle 60 which does not enterthe space S will be thrown outward by the slinger |5| into the jacket|50 and will be drained off through the pipe |55. In a similar manner,liquid from the nozzle 62 which does not enter the space S3 will bethrown outward by the slinger |52 into the jacket |50. Escape of theseliquids between the vane or slinger |52 and the bottom surface of thejacket |50 is eifectually prevented bythe centrifugal action of theslinger and also by the relatively slight clearance.

IWith these improved sealing constructions, the combustion chamber C andnozzle 23 are free to rotate at high speed and without frictionalengagement by stationary parts, but at the same time escape of theliquids supplied through the nozzles 55, 60 and 62 is electuallyprevented.

Having thus described my invention andthe advantages thereof, I do notwish to be limited to the details herein disclosed, otherwise than asset forth in the claims, but what I claim is:

1. A combustion chamber for rocket apparatus using a liquid fuel and aliquid oxidizing agent. which chamber comprises an enclosing unitarystructure having spaced inner and outer walls and providing separatedupper and lower and substantially curved recessed chamber wall portions,an axially aligned discharge nozzle for said chamber, means to rotatesaid chamber and nozzle together about the common longitudinal axisthereof, means to supply one combustion liquid to the upper recessedchamber wall portion at its upper and smaller end and adjacent saidaxis, and means to supply a second and coacting combustion liquid to thelower recessed chamber wall portion near the restricted connectionbetween the combustion chamber and the nozzle and adjacent said axis,said recessed chamber wall portions having port openings in their'largerand adjacent ends and at the zone of greatest rotative diameter of saidchamber, and said liquids being advanced to said port openings bycentrifugal force.

2. The combination in a combustion chamber as set forth in claim 1, inwhich meridian partitions are provided in said recessed chamber wallportions to hold said inner and outer walls in spaced relation and saidpartitions being eective to impart rotation to the combustion liquids'fed thereto.

3. The combination in a combustion chamber as set forth in claim l, inwhich the upper and lower port openings are circumferentially staggeredto more effectively intermingle said liquids.

4. The combination in a combustion chamber as set forth in claim 1, inwhich an annular mixing recess is provided between the adjacent ends ofsaid recessed chamber wall portions, and in which an annular slotprovides communication between said mixing recess and said combustionchamber. I

5. The combination in a combustion chamber as set forth in claim 1, inwhich an annular mixing recess is provided between the adjacent ends ofsaid recessed chamber wall portions, and in which means is provided todirect the combustion mixture from said recess and into said combustionchamber but away from the discharge end of said chamber. Y

6. The combination in a combustion chamber as set forth in claim 1, inwhich a gyroscopic counterbalancing member for said chamber is mountedadjacent the discharge end of said nozzle and is rotated by the gasesdischarged from said nozzle but with the direction of rotation inreverse with respect to that of said chamber and nozzle.

7. 'Ihe combination in a combustion chamber as set forth in claim 1, inwhich a gyroscopic counterbalancing member for said chamber is mountedadjacent the discharge end of said nozzle and is rotated by the gasesdischarged from said nozzle but with the direction of rotation inreverse with respect to that of said chamber and nozzle, and in whichmeans is provided to control the speed of rotation of saidcounterbalancing member.

8. The combination in a combustion chamber as set forth in claim 1, inwhich the spacing between the inner and outer walls of said recessedwall portions is gradually decreased as the outer diameter of said wallportions is increased, thereby providing more uniform total diametralcross sectional area in said recessed wall portions.

9.v The combination in a combustion chamber as set forth in claim 1, inwhich a xed jacket casing surrounds the rotated upper end of saidcombustion chamber, and in which an extensible weighted ring seals thespace between said rotated upper end and the adjacent edge of said fixedjacket casing when the combustion chamber is at rest, but is removedfrom contact therewith by centrifugal force when said chamber isrotated.

10. The combination in combustion chamber as set forth in claim 1, inwhich said second liquid is supplied through a xed supply nozzlecoacting with an annular opening vin the outer wall of said lowerrecessed chamber wall portion at said restricted connection.

11. The combination in a combustion chamber as set forth in claim y1, inwhich the discharge nozzle has inner and outer walls providing afrustro-conical recessed nozzle wall portion, and in which means isprovided to supply a cooling liquid to said recessed wall portionadjacent its point of smallest diameter.

12. 'I'he combination in a combustion chamber as set forth in claim 1,in which the discharge nozzle has inner and outer walls providing afrustro-conical recessed nozzle wall portion, and in which means isprovided to supply a cooling liquid to said recessed wall portionadjacent its point of smallest diameter, and in which said latter meanscomprises a xed supply nozzle coacting with an annular recess in theouter wall of said discharge nozzle.

13. The combination in a combustion chamber as set forth in claim 1, inwhich the discharge nozzle has inner and outer walls providing afrustro-conical recessed nozzle wall portion, and in which means isprovided to supply a cooling liquid to said recessed nozzle wall portionadjacent its point of smallest diameter, and in which an annularpartition separates the lower recessed wall portion of said combustionchamber from the recessed wall portion of said nozzle.

14. 'Ihe combination in a combustion chamber as set forth in claim 1,\in which the discharge nozzle has inner and outer walls providing afrustro-conical recessed nozzle wall portion, and in which means isprovided to supply a cooling liquid to said recessed wall portionadjacent its point of smallest diameter, and in which the lower end ofsaid recessed wall portion is provided with port openings helicallydisposed with respect to the nozzle axis and through which the coolingmedium is discharged, thereby facilitating rotation of said combustionchamber and nozzle.

15. The combination in a combustion chamber as setforth in claim 1, inwhich the discharge 17. The combination in a combustion chamber as setforth in claim 1, in which the adiacent ends of said recessed wallportions are spaced apart to provide an annular mixing recess, and inwhich the outer wall of said recess comprises a relatively heavyreenforcing band joining the adjacent edges of the outer walls of saidrecessed wall portions, and in which power means is provided whichcoacts with devices on said reenforcing band to provide initial rotationfor said combustion chamber.

18. The combination in a combustion chamber as set forth in claim 1, inwhich an annular mixing recess is provided between the adjacent ends ofsaid recessed chamber wall portions, and in which an annular slotprovides communication between said .mixing recess and said combustionchamber, the wall of said mixing recess being relatively thick, so thatits inner surface may be maintained at a temperature suicient to producepartial vaporization of the mixed liquids, while its surface issubstantially at the temperatures of the liquids in said recessedchamber Wall portions.

nozzle has inner and outer walls providing a frustro-conical recessednozzle wall portion, and in which a cooling liquid is supplied to saidrecessed wall portion adjacent its point of smallest diameter, and inwhich iixed supply nozzles are provided for said three liquids coactingwith annular openings in said outer lwalls, and in which centrifugalsealing means is provided to prevent leakage about said nozzles andannular openings.

16. The combination in a combustion chamber as set forth in claim l, inwhich the adjacent ends of said recessed wall portions are spaced apartto provide an annular mixing recess, and in which the outer wall of saidrecess comprises a relatively heavy reenforcing band joining theadjacent edges of the outer walls of said recessed wall Portions.

19. 'I'he combination in a combustion chamber as set forth in claim l,in which an annular mixing recess is provided between the adjacent endsof said recessed chamber wall portions, and in which an annular slotprovides communication between said mixing recess and said combustionchamber, said annular slot increasing in cross section in the directionof ilow and being effective as an injection nozzle for the intermingledcombustion liquids.

20. The combination in a combustion chamber as set forth in claim 1, inwhich the discharge nozzle has inner and outer walls providing afrustro-conical recessed nozzle wall portion; and in which means isprovided to supply a cooling liquid to said recessed wall portionadjacent its point of smallest diameter, and in which the lower end ofsaid recessed wall portion is pro vided with port openings helicallydisposed with respect to the nozzle axis and through which the coolingmedium is discharged, and said port openings being enlarged outwardlyand thereby facilitating rotation of said combustion chamber and nozzle.

ROBERT H. GODDARD.

